1. Technical Field
The present inventive concept relates to a backlight unit.
2. Description of the Related Art
A liquid crystal display device plays an important role in information display technology. In a liquid crystal display device, a liquid crystal is typically disposed between two glass substrates including respectively an upper electrode and a lower electrode. Images are displayed on the liquid crystal display device by applying voltages to the upper and lower electrodes, and changing the arrangement and direction the liquid crystal molecules to transmit or reflect light.
Since the liquid crystal display device is a light receiving device and cannot emit light on its own, a a backlight unit is typically required for irradiating light to a display panel. Specifically, the liquid crystal display device displays an image by adjusting the transmittance of light incident from the backlight unit.
In recent years, a light emitting diode (LED) is commonly used as a light source of the backlight unit in the liquid crystal display device. The LED is a semiconductor light emitting device which emits light when a current flows. The LED is widely used as a backlight unit of a lighting apparatus, electric display board, and display device due to its superior characteristics (e.g., long lifespan, low power consumption, fast response speed, excellent initial drive characteristics, etc.). As a result, the LED has proliferated into many different fields and applications.
Quantum dots may be used to increase the color purity in an LED light source. The quantum dots emit light when excited electrons transit from a conduction band to a valence band, and the wavelength of the light varies according to the sizes of the quantum dots. Since light of a shorter wavelength is emitted when the size of the quantum dots is smaller, light having a desired wavelength region may be obtained by adjusting the size of the quantum dots.
Since the quantum dot material is mainly sealed in a sealing member (such as glass), the sealing member may be damaged due to external impact. Since the quantum dot material may contain a hazardous component such as Cr, environmental pollution may result if the quantum dot material leaks from the sealing member. Thus, studies have been conducted to prevent damage to the sealing member, so as to implement white light with high color reproducibility using the quantum dot material.